As a disk device, for example, a hard disk drive (HDD) comprises a magnetic disk, a spindle motor which supports and rotates the magnetic disk, a head actuator which supports a magnetic head, a voice coil motor which drives the head actuator, a flexible printed circuit board unit and the like, which are installed in a housing.
The head actuator includes an actuator block which is rotatably supported around a support shaft, a plurality of arms each extending from the actuator block, and head suspension assemblies(, which may also be referred to as head gimbal assemblies (HGA)) connected to extending ends of the arms, respectively. The head suspension assemblies each comprise a suspension including a base plate and a load beam, a flexure (a wiring member) attached on the suspension, and a magnetic head mounted on a gimbal portion of the flexure. A slit or a slot is formed in a side surface of each arm, and the flexure is formed to extend to the actuator block while at least a part thereof is accommodated in the slit or slot in the arm. The flexure has a connection end portion formed in its extending end, and the connection end portion is electrically joined to the flexible wiring circuit (FPC) board attached to the actuator block.
In recent years, as the storage capacity of HDDs is increased, the number of magnetic disks to be installed is also increasing. In order to meet the demand of an increased number of magnetic disks, the so-called split actuator has been proposed, in which the head actuator is split into a plurality of, for example, two independently rotatable head actuators, which are further stacked one another. The actuator block of one of the head actuators is supported pivotably around the support shaft. The actuator block of the other head actuator is supported pivotably around the support shaft, and is disposed to overlay in the axial direction of the actuator block of the former actuator block.
In such a split actuator as described above, the two head actuators are pivoted independent from each other. With this structure, in order to secure smooth operation of the actuators without interfering with each other, it is necessary to provide a gap (interval) in a boundary between two actuator blocks. As the head actuator is split, the wiring board is also split into two, which are individually attached to the actuator blocks, respectively. When the positioning of attaching wiring boards individually to actuator blocks varies, the two wiring boards may interfere in the boundary portion. In order to prevent this, it is necessary to reduce the area of the wiring board itself. However, if the area of a wiring board is reduced, it becomes difficult to locate the connection pads at appropriate suitable positions to which the connection end portion of the flexure is joined.